A number of factors can have a bearing on the severity / likelihood of injury... For example:
GENDER: Females tend to be about twice as likely as males to suffer injury in an MVA (Motor Vehicle Accident).
HEIGHT: Due to the length of the spine and a greater whipping motion, TALL people are more at risk of injury in an MVA.
WEIGHT: A more slender build or lower body weight will generally mean a less muscular build, and therefore, less ability to withstand sudden movement.
BODY BUILD: Similar to the factors above, some people are more stocky and some more lanky (and more at risk of injury).
ANTICIPATION: Many accidents, especially rear end collisions, catch people totally by surprise. Being unprepared for an impact will tend to result in more flailing about on impact and thus more risk of injury.
SEAT BELT USAGE: While, over all, seat belts are a good idea and do help reduce the likelihood of fatalities, they also clearly increase neck, shoulder and back injuries by causing a greater whipping motion in the upper parts of the body.
AGE: This one is fairly obvious. People of advanced age are simply less tolerant of physical trauma. Being over 60 begins to accelerate the risk even more.
PRIOR INJURY: If the accident victim has had any significant prior injuries they will likely be at greater risk in an accident. Why? Well, think of it this way... in reality the human body is a "machine". It's very mechanical in many ways. And, the more ANY piece of machinery is "banged around", the more likely it is to break down or malfunction. While prior injuries help explain why some people may sustain greater than expected injury in a given accident, it should also be noted that prior injuries are not an excuse for the at fault party (know as the Tort Feasor) or their insurance carrier to deny liability.
PRIOR HEALTH STATUS: This one is similar to prior injuries. A person in poor or compromised health is simply less able to stand some additional assault on their well-being. Again, prior health issues do not let the Tort Feasor off the hook. So, it's not okay to bump off Grammy in a car crash, just because she's old and sick anyway.
SECONDARY IMPACT: When a car crash occurs, there will obviously be an initial impact of some sort which may be the primary cause of injury. But, there are many scenarios where the initial impact can be immediately followed by a second impact that adds to the injury. One of the most common examples is the often seen three vehicle MVA wherein the at fault party hits the victim from the rear. In this situation the "target" vehicle may be propelled forward with such force that it then strikes a third vehicle ahead, thus resulting in a secondary impact, as well as added injury, for the "target".
BODY POSITION: A significant factor that increases the probability of injury is the victim's body position at the moment of impact. This is especially important when it comes to head position. Imagine the situation where a driver is waiting at a stop sign and watching for cross traffic, with their head turned to the right or left. An impact in that position can virtually always be expected to produce greater injury than a straight forward head position.
PROXIMITY TO IMPACT: The closer a person is to any explosive force, the greater the odds of injury. In a side impact vehicle crash, car occupants on the side of impact are at greater risk.
RELATIVE VEHICLE WEIGHT: This is a biggie. While the "average" vehicle weight is about 4000 lb., as the expression is, "size matters". For example, a Kia Soul weighs about 2,844 lb. while a GMC Denali weighs about 5,414. Almost twice as much. So, at any given speed the Denali will deliver nearly twice the impact of a Kia.
VEHICLE STIFFNESS: The more rigid or stiff a vehicle is, the more the forces of impact are transferred to the vehicle occupants. While stiffer vehicles may appear to be less damaged by a crash, occupants in the vehicle are at greater risk of injury
SPEED: Speed is an even bigger deal. Increased speed that may not seem that remarkable can make a big difference in the kinetic energy of the "bullet" vehicle when it strikes the "target" vehicle. Sir Issac Newton is the father of the famous THREE LAWS OF MOTION that have been the foundation for a tremendous amount of scientific advancement. Newton's First Law of Motion is that an object in motion will continue in that motion unless acted on by an outside force. This Law explains why our earth has continued, for billions of years, to orbit the sun. There's simply been nothing to stop it...(no friction) so, it just keeps going. This Law also explains why cars have steering wheels. (LOL) A change in the angulation of the front wheels represents an "outside force" that changes the direction of motion for the car. For us, on earth, we have to deal with friction caused by a host of factors. So, because of friction, pretty much everything we see will come to a stop unless some external force keeps it in motion... such as the horse that pulls the carriage, or that souped up 409 cubic inch engine in your Hot Rod Chevy, or your brother-in-law who's pushing your car after you throw a rod. Newton's Second Law of Motion, which calculates the energy of kinetic motion, is expressed as the PHYSICS FORMULA , f = ma, wherein f = force, m = mass and a = acceleration. Newton's Third Law of Motion is the CONSERVATION OF ENERGY / MOMENTUM. What that means is that the KINETIC ENERGY (energy of motion) of the "bullet" must be transferred to the "target" during the impact. So, here are some numbers for you: At 10 MPH the average automobile (about 4000 lb.) has a kinetic energy of about 13,371 foot pounds. A "Foot Pound" is a measure of energy, and one ft.lb. is the energy it takes to raise one pound - one foot, against the force of gravity. So, if another "average" car hits you at 10 MPH, according to the laws of physics, it will deliver an impact of about 13,371 foot pounds. But, if we double the speed of the "bullet" to 20 MPH, the force of impact doesn't just double also. No, it jumps 4 times to an impact of over 53 thousand foot pounds of energy that hits you. If we go up 3 times from 10 MPH to an impact at 30 MPH, the force of impact isn't just 3 times more. Now, it's 9 times more, at a force of over 120 thousand foot pounds of energy. And, when it comes to highway speeds of 70 MPH, the kinetic energy of the "bullet" is now 50 times greater, with over 655 thousand ft. pounds of impact. Amazing. With these scientific facts in mind, it's easy to see how a person can be injured, in even what seems to be a minor accident.
When evaluating any patient who has been injured in an auto accident, these INJURY MAGNIFICATION FACTORS are variables that we take into consideration in the process of rendering an ASSESSMENT OF PATIENT INJURIES.